Certain photonic devices such as photonic integrated circuits (PICs) typically operate best when the incoming light signals have a particular state of polarization (SOP), for example the transverse-electric (TE) SOP. However, in practice the incoming light may have a different SOP (e.g. due to random polarization). Polarization controllers may be employed for dynamically regulating the SOP of incoming light. Polarization control is desirable in various situations in which a sensitivity to polarization of light exists. For example, receivers of coherent engines, modulators, certain types of fibers such as OAM fibers, and silicon photonic devices, may be particularly sensitive to polarization. The use of silicon photonics in datacenters may particularly benefit from controlling the SOP of incoming light.
Like other control schemes, polarization control can be implemented using feedback, in which control signals are adjusted based on a monitored SOP. However, currently available schemes for measuring SOP can be complex, which leads to implementation problems of cost, scalability, component count, insertion loss, and device size. Current SOP measurement schemes impose significant costs to photonic architectures which limits applications when scalability is required. It is also difficult to simplify the SOP measurement schemes without significantly increasing the complexity of the associated measurement and control algorithms.
In addition to polarization controllers, other photonic devices may also benefit from photonic measurements, such as measurements indicative of or related to SOP, or measurements which can be used for feedback control or device monitoring.
Therefore there is a need for a method and apparatus for obtaining efficient optical measurements in a photonic device that obviates or mitigates one or more limitations of the prior art.
This background information is provided to reveal information believed by the applicant to be of possible relevance to the present invention. No admission is necessarily intended, nor should be construed, that any of the preceding information constitutes prior art against the present invention.